1. Technical Field
This disclosure relates generally to surgical needle forming and, more particularly, to a progressive die apparatus and method for forming high strength surgical needles, such as surgical incision members, from needle stock material, and the resulting surgical needles or surgical incision members.
2. Description of Related Art
Surgical incision members are surgical grade suturing needles having points formed at one or both ends and preferably include surgical suturing apparatus engagement structure formed within a body portion of the needle intermediate the pointed ends. Particular surgical incision members are disclosed in commonly assigned U.S. patent application Ser. Nos. 08/260,579, filed Jun. 16, 1994 now U.S. Pat. No. 5,569,301 entitled SURGICAL INCISION MEMBERS; 29/024,594, filed Jun. 16, 1994 now abandoned entitled SURGICAL INCISION MEMBER; 06/954,013 filed Sep. 30, 1992, now abandoned entitled SUTURING APPARATUS; and 08/134, 145 filed Oct. 8, 1993, now abandoned, entitled SURGICAL SUTURING APPARATUS WITH LOADING MECHANISM, the disclosures of which are incorporated by reference herein. The suturing apparatus engagement structure is provided in the body portion of the surgical incision members to cooperate with corresponding engagement structure, such as, for example, needle engaging members or blades, on various surgical suturing apparatus. One particularly suitable apparatus for manipulation of surgical incision members is disclosed in commonly assigned U.S. patent application Ser. No. 08/134,145 filed Oct. 8, 1993, now abandoned, entitled SURGICAL SUTURING APPARATUS WITH LOADING MECHANISM, the disclosure of which is incorporate by reference herein. Apparatus engagement structure in the body portion of the needle blank along with cooperating engagement structure on the surgical suturing apparatus facilitates repeatedly passing the surgical incision member between a pair of arms or jaws in the suturing apparatus. In this manner the surgical suturing apparatus is able to securely and precisely control the surgical incision member for very effective, rapid and precise suturing of tissue. The apparatus engagement structure may be in the form of notches, holes, or crimps, etc., formed in the body portion of the surgical incision member.
Additionally, surgical incision members may have various suture attachment structure formed in the body portion intermediate the pointed ends. Preferably, the suture attachment structure is positioned intermediate the apparatus engagement structure. The surgical incision members may be curved with a radius substantially equal to the distance between a pivot point and engagement structure on a pair of jaws. Alternatively, the surgical incision member may be relatively straight to facilitate transfer of the surgical incision member between a pair of parallel moving jaws or arms. The parallel moving arm or jaw structure may be in the form of arms or jaws which move perpendicular to each other axis or parallel to each other. One or both jaws of the suturing apparatus may move.
Due to the added manufacturing equipment necessary to produce apparatus engagement and suture attachment structure within the body portion of a needle, the manufacture of surgical incision members may often become complicated and costly. For example, one method of manufacturing the surgical incision member is by a process called metal injection molding or "MIM". The MIM manufacturing process tends to be costly and thus may adversely affect the otherwise desirable characteristics and traits of a surgical suturing apparatus utilizing surgical incision members.
The production of needles in general involves many processes and different types of machinery in order to prepare quality needles from raw stock. These varying processes and machinery become more critical in the preparation of surgical grade needles where the environment of intended use is in humans or animals. Some of the processes involved in the production of surgical grade needles include, inter alia, straightening wire stock, cutting needle blanks from the wire stock, tapering or grinding points on one or both ends of the blank, and providing structure for receiving a suture thread at an end of the blank or at a location intermediate the ends. As used herein, the term "needle blank" refers to a piece of needle stock material at various stages of completion but not fully formed into a surgical grade needle suitable for use during surgical procedures. Additionally, one skilled in the art will appreciate that flat surfaces may be formed on sides of the blank, typically by flat pressing portions of the needle blank to facilitate grasping by surgical instrumentation. Curving of the needle blank may also be performed where curved needles are desired. When providing curved needles for surgical procedures it is desirable for the needles to have a specified curvature, i.e., a predetermined radius of curvature. The desired radius of curvature for the finished needle varies with specific applications.
Surgical needles or surgical incision members formed by the MIM process or from wire needle stock material may lack certain characteristics found desirable when used in tough body tissues. These characteristic may include point sharpness, resistance to bending, ductility, etc. Bend strength may be compromised when it is desirable to maintain a specified ductility.
Surgical incision members, in particular, typically require several processes to form the finished product. These processes may include cutting and curving needle stock material to form needle blanks, altering or refining the tip configurations and curvature radius, punching or drilling the blank to form a suture hole and/or notching the blank to provide engaging structure for cooperative instrumentation. However, as noted above, when the surgical incision members are formed from wire needle stock material the resultant bend strength may be insufficient where the intended use of the needle is in tough tissues, such as, for example, ligaments and tendons, such as Cooper's ligament overlying pelvic bone
Conventional needle processing is, in large part, a labor intensive operation requiring highly skilled labor and sophisticated machinery. One disadvantage to conventional needle processing is that most needle processing operations, such as, for example, cutting the blanks from stock, tapering the stock to form points, flat and side pressing of the body portion of the blanks, curving the blanks, notching, hole drilling, etc., are performed in batch operations on separate processing machines. One particular suitable progressive die apparatus for performing multiple operations on a single machine to produce surgical incision members is disclosed in commonly assigned U.S. patent application Ser. No. 08/320,015, filed Oct. 7, 1994, now Pat. No. 5,553,447, entitled PROGRESSIVE DIE APPARATUS FOR FORMING SURGICAL INCISION MEMBERS, the disclosure of which is incorporated by reference herein. This apparatus progressively forms a single needle at a time.
In some instances, during surgery a sharply pointed needle has been found to stick into or catch edges of bone resulting in over penetration and dulling of the needle point. Thus, it would be desirable to have an apparatus for progressively forming a large number of high strength surgical needles and, in particular, surgical incision members, resistant to dulling or bending through tough tissue or when bone is contacted. It also would be desirable to provide an apparatus and method for forming a large number of high strength surgical needles from needle stock material in a very short time and with a minimal amount of machinery. It would also be desirable to have an apparatus and method of imparting a predetermined optimal point geometry to a needle blank. It would further be desirable to have an apparatus and a method of progressively forming opposed pairs of curved surgical incision members having a desired radius of curvature. It would be still further desirable to have an apparatus and a method of simultaneously imparting apparatus engagement structure and drill point guide holes, or suture attachment structure, in the body portion of opposed pairs of surgical incision members. It would be especially desirable to provide a high strength surgical needle suitable for use in tough body tissues. It would be further desirable to provide a surgical needle having an optimal point/tip geometry.